Communication system



,Jan. '18, 1944.

R. H. CAMPBELL COMMUNICATION SYSTEM v Filed Aug. 3, 1942 1 WNN ZZZ/6202M273,056 ZZ W 6' M Patented Jan. 18, 1944 2 COMMUNICATION SYSTEM RichardR. Campbell, Racine, -Wis., assignor to Webster Electric Company,

poi'ation of Delaware Application August 3, 1942, Serial No. 453,342

8 Claims.

The present invention .relates to communication systems and moreparticularly to intercommunicating systems of the loudspeaking type.

One of the objects of the present invention is the provision of a newand improved communieating system of the loudspeaking type comprisingone or more stations of the so-called master type, each of whichincludes an amplifier and a communication direction control switch, andone or more so-called stations of the type having no amplifier orcommunication direction control switch, in which operators at stationsof the latter type can signal operators at master stations that theydesire to communicate with them.

A further object of the present invention resides in the provision of anew and improved communicating system ofthe character specified whereinoperators at substations can not only signal master stations, but aresimultaneously apprised as to whether or not the signal has sounded atthe master station.

- Another object of the present invention is to provide a new andimproved communicating system of the character specified whereinoperators at substations can signal the master stations and a signal isproduced at the substation in the event the called station is not busy.

A further object of the present invention is the provision of a new andimproved communicating system of the loudspeaking type in which theswitching operations for signaling and communicating are simplified.

Other objects and advantages or the present invention will becomeapparent from the ensuing description in which reference is had to theac-.

companying drawing, the single figure of which is a diagrammaticrepresentation of a system embodying the invention.

In the embodiment of the invention illustrated in the figure, the systemis shown to include two master stations indicated by referencecharacters I and 2 and three substations indicated by referencecharacters 3, 4, and 5. It should be understood, however, that thesystem may include more than the indicated number of stations of eithertype.

The master stations are identical and consequently it is deemednecessary to describe in detail but one f these and to indicate thecorresponding apparatus at the other by the same reference charactersfollowed by the sufilx 2.

The apparatus at station I includes an amplifier ID, a loudspeaker I2 01the permanent magnet type adapted to be utilized both as a receiver anda microphone, a three-position combined Racine, Wis., a corcommunicationdirection control and power switch l4 and a signal producing device l6which may take the form of a buzzer and which is supplied with powerthrough a transformer I8.

The amplifier l8 may be of any conventional construction and be suppliedwith power through the power supply lines 20. The amplifier iconditioned to be inoperative when the switch I4 is in its indicateduppermost position. At this time the B supp y to the amplifier is brokenby the switch blade 22 in circuit with the B supply conductor 24. Whenthe switch II, which, of course, includes the-blade 22, is operated toeither of its two other positions, the amplifier is rendered immediatelyoperative upon completion of the 3 supply circuit.

The communication direction control switch I4 is of the three-positiontype. In one position, that indicated, the loudspeaker I2 is connectedto a circuit consisting of the pair of conductors 26 by means of switchblades 28 and a circuit consisting of the two conductors 38. In theintermediate position, the amplifier input i connected to conductors 26through the switch blades 28 and the amplifier input circuit includingthe two conductors 32, and the amplifier output is connected to theloudspeaker through a circuit including the output conductors 34, theswitch blades 36, the pai or conductors 38, and the previously referredto conductors 38. In the third or lowermost position of thecommunication control switch, the connections of the loudspeaker andcircuit 26 to the amplifier loudspeaker being connected to the amplifierinput through conductors 30, 38, switch blades 36, conductors 48, andthe input conductors 32, and circuit 28 being connected to the amplifieroutput through the switch blades 28 and conductors 34.

It is preferred that the various switch blades constituting switch l4.be operable simultaneously and they have been thus illustrated as beingmgglliyanically connected. The er biased to return from its lowerm tionto its intermediate position by a sg r i n g l although it can be biasedto return to its upper- 3105b position from either of its two otherposions.

The master station includes a plurality of station selector switches 43,44, and 45, whereby the communication circuit 26 may b connected tocircuits individual to the substations 3, 4, and 5. These stationselector switches are connected in parallel to the communication circuit26 so that when any of the switches are closed the circuit 26 isconnected to the interstation circuit indiswitch is also prefvidual tothe stations associated with-the selector switches.

The master station also includes a station selector switch 46 adapted tobe closed to signal master station 2. The switch 46 is connected inparallel with the other selector switches.

The master station I is also provided with a two-position signal andcommunication circuit controlling switch 48 adapted in one (itsindicated) position to connect the signal producing device I6 to aninterstation circuit including the pair of conductors 50 extending toother stations in the system. In this position of the switch, thecircuit 50 and signal producing device I6 are connected in series withthe secondary winding 52 of the transformer l8, the circuit includingthe pair of conductors 54.. In the second position of the switch 48, thecircuit 50 is connected to the circuit 26 through a pair of branchconductors 56. As a result, the circuit 50 may be utilized either as asignaling or communication circuit.

The substations hav interstation circuits individual thereto, thesebeing indicated by reference characters 63, 64, and" 65, respectively.

The apparatus at the various substations is identical and it is,therefore, deemed necessary to describe in detail only that at station3. The substation includes a loudspeaker 66 utilizable both as areceiver and a microphone and a communication and signal circuitcontrolling switch including the two switch blades 68. The switch 66normally occupies a position connecting a loudspeaker 66 to interstationcircuit 63 and is operable to connect the loudspeaker either to circuit50 or to circuit 60-2 in order that the operator at the substation maysignal the operators at the master stations that be desires tocommunicate with them. When the operator at station 3 desires to signalthe operator at station I, the switch 66 is moved to the left thereby toconnect the loudspeaker 66 to circuit 50 through conductors l0. Whentheoperator at station 3 demost positions, and the switches 66 at thesubstations connect the loudspeakers thereat to their respectiveinterstation circuits.

In the event the operator at station I desires to communicate with anyof the substations, say

station 3, then the selector switch 43 is closed to interconnectcircuits 26 and 63 and the operator at station I operates thecommunication direction control switch I4 to its lowermost position toconnect the loudspeaker I2 to the input of the amplifier and the circuit26 to the output of the amplifier, thus conditioning the circuits forcom munication from station II to station 3. To receive a reply fromstation I, the communication direction control switch is operated to itsintermediate position to reverse the connections of loudspeaker I2 andcircuit 26 to the amplifier thereby to condition these for communicationfrom station 3 to station I.

when station I desires to communicate with any of the other substations,the operation corresponds to that described above except for the closureof the proper selector switch for the desired substation.

When the operator at a substation desires to call a master station, as,for instance, when the operator at station 3 desires to call station I,then the switch 68 is moved to the left to connect loudspeaker 66 tocircuit 50. This operation completes a circuit through the signalproducing device, the secondary 52 of transformer l8, and loudspeaker66, placing all these in series, with the result that the signalproducing device I6, which may be a buzzer as heretofore indicated,produces an audible sound at the master station and the loudspeaker 66produces an audibl sound at the substation, thus indicating to theoperator at the latter that station I is not busy. To reply to the call,it is necessary for the operator at station I simply to move switch 48from its uppermost to its lowermost position thereby interconnectingcircuits 26 and 50 through the switch and through the branch circuit 56.Thereafter communication between stations I and 3 is carried on inopposite directions under the control of the operator at station I whomanipulates the communication direction control switch I4 between itslowermost and intermediate positions. At this time the buzzer I6 atstation I is disconnected from station 60 so that should some othersubstation or master station desire to signal station I, no audiblesound is produced either at station I or the calling station. Asaresult, the operator at the calling station is apprised that station Iis busy.

In the event that master station I desires to communicate with masterstation 2, the operator at the former closes a station selector switch46, thereby interconnecting circuits 26 and 50-2. This interconnectioncloses a circuit through the buzzer I6'2 which circuit extends throughthe secondary winding 52-2, the circuits 50-2, 26, and through theloudspeaker I2 at station I. The result is the production of an audiblesignal by the buzzer at station 2 and an audible signal by theloudspeaker I2 at station I. To reply, the operator at station 2 movesswitch 48-2 from its uppermost to its lowermost position, therebyconnecting the loudspeaker I2-2 at station 2 to the circuit 50-2 andthereafter communication is carried on in opposite directions under thecontrol of the operator at station I who again has merely to operate thecommunication direction control switch I4 between its intermediate andlowermost positions.

It may be noted that when one of the master stations calls andcommunicates with one of the substations, or a master station, as, forinstance, when station I calls station 3 or station 2, that the switch48 at station I need not be operated from its indicated signal circuitclosing position to a communication circuit closing position. As aresult, other stations may complete signaling circuits to station I toindicate they desire to communicate therewith. In the event it is notdesired to have other stations able to signal in this manner when one ofthe master stations is in communication with another station, thenswitch 48 may be constructed as a three-position switch having a circuitopening position in addition to those indicated so that it can beoperated to open both the signal and communication circuits whendesired. If desired, this switch could be connected to the variousstation selector switches in such manner that it is operated to itsassacvs circuitopening position whenever one of the station selectorswitches is closed.

Although the invention has been disclosed in connection with specificdetails of a preferred embodiment, it should be understood that suchdetails are not intended to be limitative of the invention except in sofar as set forth in the accompanying claims. The system is susceptiblenot only of the modifications heretofore indicated, but also of others.For instance, the master station selector switches 48 may close circuitsto the two-way communication circuits of other stations rather thancompleting circuits to the signaling circuits at the master stations asindicated. This would enable master stations immediately to call othermaster stations as distinguished from signaling other master stations.

Having thus described my invention, what I claim as new and desire tosecure by United States Letters Patent is:

1. In a communication system of the loudspeaking type including a firststation having a receiver utilizable also as a microphone, an amplifierand a communication direction control switch and a second stationhaving a receiver utilizable also as a microphone, the combinationincluding, signal producing means and switch means at the first station,an interstation circuit connecting said stations, circuits controlled bysaid switch means for selectively connecting said interstation circuitto said signal producing means or to said communication directioncontrol switch, and means including a switch at the second station forsimultaneously connecting said receiver to said interstation circuit andcompleting a circuit to said signal producing means.

2. In a communication system of the loudspeaking type including one ormore stations .of a first type each having a receiver utilizable also asa microphone, an'amplifier and a communication direction control switchand one or more stations of a second type each having a receiverutilizable also as a microphone, the combination including, signalproducing means and switch means at stations of the first type,interstation circuits individual to each of said stations of the firsttype extending to stations of the second type and to other stations ofthe same type, circuits controlled by said switch means at stations ofthe first type for selectively connecting the interstation circuitassociated with the station to the signal producing means or to thecommunication direction control switch, and means including switches atstations of the second type for simultaneously connecting the receiversthereat to said interstation circuits and completing circuits to thesignal producing means.

3. In a communication system of the loudspeaking type including one ormore stations of a first type each having a receiver utilizable also asa microphone, an amplifier and a communication direction control switchand one or more stations of a second type each having a receiverutilizable also as a microphone, the combination including, signalproducing means and switch means at stations of the first ype,interstation circuits individual to each or said stations of the firsttype extending to stations of the second type, circuits controlled bysaid switch means at stations of the first type for selectivelyconnecting the interstation circuit associated with the station to thesignal producing means or to the communication direction control switch,and means including switches at stations of the second type torsimultaneously connecting the receivers thereat to said interstationcircuits and completing circuits to the signal producingsecond stationfor connecting said receiver to said interstation circuit and completinga circuit through said signal producing means and receiver to give anaudible signal at both stations when said switch means at thefirststation connects the interstation circuit to said signal producingmeans.

5. In a communication system or the loudspeaking type including one. ormore stations of a type each having a receiver utilizable. also .as amicrophone, an amplifier and a communication direction control switchand one or more stations of a type eachhaving a receiver utilizable alsoas a microphone, the combination including,, signal producing means andswitch means at stations of the first type, interstation circuitsindividual to stations of the first type connecting statiqns of thesecond type to stations of the first type and stations of the first typeto others of the same type, circuits controlled by said switch means atstations of the first type for selectively connecting the in-.terstation circuit associated with the station to the signal producingmeans or to the communication direction control switch at the station,and

means including switches at stations of the second type for connectingthe receivers thereat to I tions of a type eachhaving a receiverutilizable also as a microphone, the combination including. si nalproducing means and switch means at stations of the first type,interstation circuits individual to stations of the first typeconnecting stations of the second type to stations of the first type,circuits controlled by said switch means at stations of the first typefor selectively connecting the interstation circuit associated with thestation to the signal producing means or to the communication directioncontrol switch at the station, and means including switches at stationsof the second type for connecting the receivers thereat to saidinterstation circuits and completing circuits through said signalproducing means and receiver to give an audible signal at both types ofstations when said switch means at stations of the firsttype connect theinterstation circuit individual thereto to the signal producing meansthereat.

' to said signal producing means or to said communication directioncontrol switch, a station selector switch at the first station forconnecting said communication direction control switch to said firstinterstation circuit, and means including a switch at the second statidnnormally connecting said receiver to said first interstation circuit andoperable to complete a circuit through said second interstation circuit,the signalproducing means at the first station and the receiver at thesecond station to. give an audible signal at both stations when saidswitch means at the first station connects the second interstationcircuit to said signal producing means.

assacvs also as amicrophone, the combination including, signal producingmeans and switch means atstations or the first type, combined signalingand communication circuits individual to stations of the first typeconnecting stations of the second type to stations of the first type andstations of the first t to others of the same type, com- 8. In acommunication, system of the loud.

speaking type including one or more stations 01 a type each having areceiver utilizable also as a microphone, an amplifier and acommunication direction control switch and one or more stations oi atype each having a receiver utilizable munication circuits betweenstations 0! the first and second types, circuits controlled by said,

station to the signal producing means or to the communication directioncontrol switch at the station, station selector switches at stations ofthe first type for connecting the communication direction controllingswitches thereat to said communication circuits, and means includingswitches at stations of the second type normally connecting thereceivers thereat to their respective communication circuits andoperable to complete circuits through said combined signaling andcommunication'circuits, signal producing means at stations of the firsttype and the receivers at stations at the second type to give an audiblesignal at both types of stations when said switch means at stations ofthe first type connect the combined signaling and communication circuitindividual thereto to the signal producing means thereat.

RICHARD H. CAMPBELL.

